Forge Minecraft crashing due to WorldEdit problems.

I have downloaded WorldEdit for (forge 1.14 version) to be used on my builds. I have Forge installed. When I load a world, WorldEdit would not function and would randomly crash. The crash is apparently due to "BigTreeFeature".

Here is the error message:

The game crashed whilst exception in server tick loop
Error: java.lang.NoClassDefFoundError: net/minecraft/world/gen/feature/BigTreeFeature

Here is the crash report:

Minecraft Crash Report -------- Minecraft Crash Report ----// Uh... Did I do that?
Time: 21/03/20 22:03Description: Exception in server tick loop
java.lang.NoClassDefFoundError: net/minecraft/world/gen/feature/BigTreeFeature at com.sk89q.worldedit.forge.ForgeWorldEdit.getWorld(ForgeWorldEdit.java:315) ~[?:?] {re:classloading} at com.sk89q.worldedit.forge.ForgeWorldEdit.onPlayerInteract(ForgeWorldEdit.java:236) ~[?:?] {re:classloading} at net.minecraftforge.eventbus.ASMEventHandler_2_ForgeWorldEdit_onPlayerInteract_PlayerInteractEvent.invoke(.dynamic) ~[?:?] {} at net.minecraftforge.eventbus.ASMEventHandler.invoke(ASMEventHandler.java:80) ~[eventbus-2.0.0-milestone.1-service.jar:?] {} at net.minecraftforge.eventbus.EventBus.post(EventBus.java:258) ~[eventbus-2.0.0-milestone.1-service.jar:?] {} at net.minecraftforge.common.ForgeHooks.onRightClickBlock(ForgeHooks.java:787) ~[?:?] {re:classloading} at net.minecraft.server.management.PlayerInteractionManager.func_219441_a(PlayerInteractionManager.java:315) ~[?:?] {re:classloading} at net.minecraft.network.play.ServerPlayNetHandler.func_184337_a(ServerPlayNetHandler.java:853) ~[?:?] {re:classloading} at net.minecraft.network.play.client.CPlayerTryUseItemOnBlockPacket.func_148833_a(SourceFile:36) ~[?:?] {re:classloading} at net.minecraft.network.play.client.CPlayerTryUseItemOnBlockPacket.func_148833_a(SourceFile:10) ~[?:?] {re:classloading} at net.minecraft.network.PacketThreadUtil.func_225383_a(SourceFile:21) ~[?:?] {re:classloading} at net.minecraft.network.PacketThreadUtil$$Lambda$5074/306421152.run(Unknown Source) ~[?:?] {} at net.minecraft.util.concurrent.TickDelayedTask.run(SourceFile:18) ~[?:?] {re:classloading} at net.minecraft.util.concurrent.ThreadTaskExecutor.func_213166_h(SourceFile:144) ~[?:?] {re:classloading,pl:accesstransformer:B} at net.minecraft.util.concurrent.RecursiveEventLoop.func_213166_h(SourceFile:23) ~[?:?] {re:classloading} at net.minecraft.server.MinecraftServer.func_213166_h(MinecraftServer.java:731) ~[?:?] {re:classloading,pl:accesstransformer:B} at net.minecraft.server.MinecraftServer.func_213166_h(MinecraftServer.java:141) ~[?:?] {re:classloading,pl:accesstransformer:B} at net.minecraft.util.concurrent.ThreadTaskExecutor.func_213168_p(SourceFile:118) ~[?:?] {re:classloading,pl:accesstransformer:B} at net.minecraft.server.MinecraftServer.func_213205_aW(MinecraftServer.java:714) ~[?:?] {re:classloading,pl:accesstransformer:B} at net.minecraft.server.MinecraftServer.func_213168_p(MinecraftServer.java:708) ~[?:?] {re:classloading,pl:accesstransformer:B} at net.minecraft.util.concurrent.ThreadTaskExecutor.func_213160_bf(SourceFile:103) ~[?:?] {re:classloading,pl:accesstransformer:B} at net.minecraft.server.MinecraftServer.func_213202_o(MinecraftServer.java:693) ~[?:?] {re:classloading,pl:accesstransformer:B} at net.minecraft.server.MinecraftServer.run(MinecraftServer.java:641) [?:?] {re:classloading,pl:accesstransformer:B} at java.lang.Thread.run(Thread.java:745) [?:1.8.0_51] {}Caused by: java.lang.ClassNotFoundException: net.minecraft.world.gen.feature.BigTreeFeature at java.lang.ClassLoader.findClass(ClassLoader.java:530) ~[?:1.8.0_51] {} at java.lang.ClassLoader.loadClass(ClassLoader.java:424) ~[?:1.8.0_51] {} at cpw.mods.modlauncher.TransformingClassLoader.loadClass(TransformingClassLoader.java:101) ~[modlauncher-5.0.0-milestone.4.jar:?] {} at java.lang.ClassLoader.loadClass(ClassLoader.java:357) ~[?:1.8.0_51] {} ... 24 more

A detailed walkthrough of the error, its code path and all known details is as follows:---------------------------------------------------------------------------------------
– System Details --Details: Minecraft Version: 1.15.2 Minecraft Version ID: 1.15.2 Operating System: Windows 10 (amd64) version 10.0 Java Version: 1.8.0_51, Oracle Corporation Java VM Version: Java HotSpot(TM) 64-Bit Server VM (mixed mode), Oracle Corporation Memory: 1612221672 bytes (1537 MB) / 2147483648 bytes (2048 MB) up to 2147483648 bytes (2048 MB) CPUs: 4 JVM Flags: 9 total; -XX:HeapDumpPath=MojangTricksIntelDriversForPerformance_javaw.exe_minecraft.exe.heapdump -Xss1M -Xmx2G -XX:+UnlockExperimentalVMOptions -XX:+UseG1GC -XX:G1NewSizePercent=20 -XX:G1ReservePercent=20 -XX:MaxGCPauseMillis=50 -XX:G1HeapRegionSize=32M ModLauncher: 5.0.0-milestone.4+67+b1a340b ModLauncher launch target: fmlclient ModLauncher naming: srg ModLauncher services:  /eventbus-2.0.0-milestone.1-service.jar eventbus PLUGINSERVICE  /forge-1.15.2-31.1.27.jar object_holder_definalize PLUGINSERVICE  /forge-1.15.2-31.1.27.jar runtime_enum_extender PLUGINSERVICE  /accesstransformers-2.0.4-shadowed.jar accesstransformer PLUGINSERVICE  /forge-1.15.2-31.1.27.jar capability_inject_definalize PLUGINSERVICE  /forge-1.15.2-31.1.27.jar runtimedistcleaner PLUGINSERVICE  /forge-1.15.2-31.1.27.jar fml TRANSFORMATIONSERVICE  FML: 31.1 Forge: net.minecraftforge:31.1.27 FML Language Providers:  [email protected] minecraft@1 Mod List:  forge-1.15.2-31.1.27-client.jar Minecraft {[email protected] DONE} Smaller-Nether-Portals-Mod-1.15.1.jar Smaller Nether Portals {[email protected] DONE} forge-1.15.2-31.1.27-universal.jar Forge {[email protected] DONE} WorldEdit-1.14.4.jar WorldEdit {[email protected];61bc012 DONE} Player Count: 1 / 8; [ServerPlayerEntity['Hummingbirdmoth'/230, l='New World', x=-197.16, y=4.00, z=207.28]] Data Packs: vanilla, mod:forge (incompatible), mod:smallernp (incompatible), mod:worldedit (incompatible) Type: Integrated Server (map_client.txt) Is Modded: Definitely; Client brand changed to 'forge'